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Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium radioactively decays, usually by emitting an alpha particle.
Uranium ores with low thorium concentrations can be purified to produce gram-sized thorium samples of which over a quarter is the 230 Th isotope, since 230 Th is one of the daughters of 238 U. [27] The International Union of Pure and Applied Chemistry (IUPAC) reclassified thorium as a binuclidic element in 2013; it had formerly been considered ...
Element symbols for chemical elements ... Baskerville wrongly believed carolinium to be a new element. Was actually thorium. The symbol Cn is now used ... Uranium: 92 ...
Beginning with naturally occurring uranium-238, this series includes the following elements: astatine, bismuth, lead, polonium, protactinium, radium, radon, thallium, and thorium. All of the decay products are present, at least transiently, in any uranium-containing sample, whether metal, compound, or mineral. The decay proceeds as:
Uranium-233 is made from thorium-232 by neutron bombardment. Uranium-235 is important for both nuclear reactors (energy production) and nuclear weapons because it is the only isotope existing in nature to any appreciable extent that is fissile in response to thermal neutrons, i.e., thermal neutron capture has a
Thorium reacts with hydrogen to form the thorium hydrides ThH 2 and Th 4 H 15, the latter of which is superconducting below the transition temperature of 7.5–8 K; at standard temperature and pressure, it conducts electricity like a metal. [12] Thorium is the only metallic element that readily forms a hydride higher than MH 3. [31]
Three of these elements, bismuth (element 83), thorium (90), and uranium (92) have one or more isotopes with half-lives long enough to survive as remnants of the explosive stellar nucleosynthesis that produced the heavy elements before the formation of the Solar System.
Neptunium is a chemical element; it has symbol Np and atomic number 93. ... Thorium, protactinium, and uranium, with their dominant oxidation states of +4, +5, and +6 ...